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AM3 cpu on AM2 mobo

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October 30, 2009 9:22:05 PM

Hello people;

I have an AM2 mobo, an MSI K9AG Neo2-Digital, running an Athlon 64 3800+ (ie 2.4Ghz).
Now, the MSI website itself is out of date concerning cpu support,
but I learned on www.cpu-upgrade.com
that my mobo will support most Athlon II and Phenom II CPUs, if I install the latest bios version.

I am wondering if I should go for a 2-core or a 4-core,
because I don't know if my AM2 mobo could be a bottleneck for such 2-core or even 4-core CPUs.
My mobo has DDR2-800 memory, but I already learned that this should not have any noticeable performance impact compared to standard DDR3.

So I am left with 1 question: Could there be anything else on my mobo which could limit the performance of a modern AM3 cpu?
My mobo is limited to a TDP of 95 watts, so I know I should not go for a cpu which needs more.

So there is 1 thing left which puzzles me:
My mobo is limited to a HyperTransport 2.0 1Ghz bus speed.
I don't know how to calculate its bandwith, nor do I know how much HT bandwith AM3 2-core or 4-core cpus need.

So, I am prepared to buy a 4-core Athlon II or Phenom II, but only if I know that my mobo won't be a noticeable limiting factor.
If my mobo can be a limiting factor, then should I would better go for a high speed 2-core Athlon II or Phenom II.

I am not a true gamer (I've played Bioshock, but that game runs perfectly with my current Athlon 64 3800+ and my ATI X1650 GPU).

Any advice about upgrading to an AM3 cpu on a AM2 (without the +) mobo would be greatly appreciated.

Thanks very much in advance;
Carl




More about : am3 cpu am2 mobo

a b à CPUs
October 30, 2009 10:35:23 PM

it will be a big bottleneck

AM2 have really slow FSBs it will considerably slow down the proc especially the phenom
a b à CPUs
October 30, 2009 10:38:32 PM

Your mobo won't be a huge drawback, a few percent here or there but nothing really major.

At 95w you are a bit restricted on the Phenom II's anyway, though I believe you can get a 945 at 95w.

I'm a big believer in cpu and gpu being very closely matched to get the best performance, so in your case I'd be looking to upgrade both. With that in mind I think going for an x2 or x3 phenom II and perhaps an HD 4670 gpu would work well.

Tbh there is so little between the new athlons and the x2/x3 phenom's it really is choose what you fancy most.
Related resources
a b à CPUs
October 30, 2009 10:40:40 PM

^ really? not a bottleneck?
a b à CPUs
October 30, 2009 10:46:05 PM

It's not that bad.

HyperTransport Version Year Max. HT Frequency Max. Link Width Max. Aggregate Bandwidth(bi-directional) Max. Bandwidth at16-Bit Max. Bandwidth at 32-Bit
1.0 2001 800 MHz 32-bit 12.8 GB/s 3.2 GB/s 6.4 GB/s
1.1 2002 800 MHz 32-bit 12.8 GB/s 3.2 GB/s 6.4 GB/s
2.0 2004 1.4 GHz 32-bit 22.4 GB/s 5.6 GB/s 11.2 GB/s
3.0 2006 2.6 GHz 32-bit 41.6 GB/s 10.4 GB/s 20.8 GB/s
3.1 2008 3.2 GHz 32-bit 51.2 GB/s 12.8 GB/s 25.6 GB/s

Forgive the lack of formatting, but you can pretty much see it's not gonna hugely impact performance on a lower end Phenom II or Athlon II at 95W.
a c 159 à CPUs
October 30, 2009 10:49:17 PM

Your board won't run any am3 cpus according to MSI's website. I suggest a 5800 oem 76w am2 sold at Starmicro for $64 plus shipping. It runs at 3.0 ghtz and is the fastest dual core cpu on your board's "cpu support" list. Newegg doesn't carry these anymore. At starmicro's website, do a search typing "am2". The 5800 is about two-thirds down the page.
a b à CPUs
October 31, 2009 12:04:12 AM

why aren't Intel FSBs that high?
October 31, 2009 12:18:01 PM

o1die said:
Your board won't run any am3 cpus according to MSI's website. I suggest a 5800 oem 76w am2 sold at Starmicro for $64 plus shipping. It runs at 3.0 ghtz and is the fastest dual core cpu on your board's "cpu support" list. Newegg doesn't carry these anymore. At starmicro's website, do a search typing "am2". The 5800 is about two-thirds down the page.



Yes I know.
But according to www.cpu-upgrade.com it is the MSI website itself which is not up-to-date, and according to the list of supported CPUs on cpu-upgrade, my mobo suports most of the new Athlon II's and Phenom II's.

I've had the same in the past: A Dell Pentium II pc only supported PIIs up to 400Mhz, but in the end I managed to install a Celeron at 1.2 Ghz. Does anyone else remember the happy upgrade-days with the Tualatin Celerons? :-)
Boy, they were a MIGHTY upgrade. That Celeron turned my Pentium II system into the longest running pc I have ever had.
And so now I hope that with my AM2 mobo I can do the same with an Athlon II or a Phenom II, and keep my pc for another 2-3 years.

Now I 'm at it, does anyone know about the reliability of the cpu-list on www.cpu-pgrade.com ?
It seems they don't do anything else but post cpu-support on hundreds of mobos, so I suppose they know what they're doing.

Thanks for the post!
Carl
October 31, 2009 12:36:19 PM

jennyh said:
It's not that bad.

HyperTransport Version Year Max. HT Frequency Max. Link Width Max. Aggregate Bandwidth(bi-directional) Max. Bandwidth at16-Bit Max. Bandwidth at 32-Bit
1.0 2001 800 MHz 32-bit 12.8 GB/s 3.2 GB/s 6.4 GB/s
1.1 2002 800 MHz 32-bit 12.8 GB/s 3.2 GB/s 6.4 GB/s
2.0 2004 1.4 GHz 32-bit 22.4 GB/s 5.6 GB/s 11.2 GB/s
3.0 2006 2.6 GHz 32-bit 41.6 GB/s 10.4 GB/s 20.8 GB/s
3.1 2008 3.2 GHz 32-bit 51.2 GB/s 12.8 GB/s 25.6 GB/s




Jennyh, Thank you for the advice and the HT bandwith list.
I read somewhere on Wiki that AMD CPUs only use half of the 32-bit bandwith of HT, so it's the 16-bit figures we need to look at.

For everybody:
So, I stay stuck on the question wether or not the maximum HT frequency of my mobo (HT 2.0 1Ghz) could bottleneck a modern X2 or X4 Athlon II or Phenom II.
Certainly not while doing office work, but what about playing a "recent" game (I have Bioshock) or video editing.
Does anyone know what HT bandwith an X2 or X4 needs for these types of jobs?
I can only guess that an X4 needs A LOT of bandwith if you want it to run antivirus, Windows, and some other demanding application(s) at once without being bottlenecked by the HT bus.

Or has anyone else ever put an Athlon II or Phenom II on a 690G mobo?
Surely I am not the only one in the world with a 690G mobo, they sold millions of them, so I'm probably not the only one trying to upgrade ;-)
And my mobo is not THAT old, is it? It' not that I'm trying to put a P4 on a Pentium 1 mobo ;-)

Thanks again for all the posts, you guys are very helpful.
Carl


a b à CPUs
October 31, 2009 2:33:04 PM

I was trying to find more on it but it's difficult info to get hold of. I'll keep looking, I dont' *think* it should be a huge issue with a 95w cpu but of course it's worth finding out for sure.
October 31, 2009 7:57:48 PM

jennyh said:
I was trying to find more on it but it's difficult info to get hold of. I'll keep looking, I dont' *think* it should be a huge issue with a 95w cpu but of course it's worth finding out for sure.


Yes indeed, I've been looking around too, but I don't really know many sites like this. Only know this one and Anandtech.
They both have tested these new CPUs, but each time on AM2+ or AM3 mobos (with higher HT speeds), not on AM2 mobos.

The only reason why I am afraid of buying a triple or quad core is exactly that the HT speed might be a bottleneck.
If that's the case, it would be a waste of money because I better would have chosen a fast dual core.
Also, the HT question puzzles me about cache:
This may sound the opposite of logic, but if HT speed could be an issue, then maybe buying a Phenom with larger caches could could be a beter choice than an Athlon II.
Sounds strange, but I think that if HT speed is an issue, a Phenom X2 could be a better choice, exactly because it has more cache, and hence it needs a little less DDR2-access.

Thanks again mate. Don't look for too long, I'll try to look further also. After all, it's my problem, not yours.
I only hope that you're interested in the technical questions I ask myself :-)

Dear people at Tom's: There are millions of people who are in my situation: They too have an AM2 (non-plus) mobo. Many of them are probably also looking for a cpu upgrade. Do you know of anyone who has tested the performance impact of an AM2 (again, non-plus) mobo on these would-be ideal Athlon II and Phenom II CPUs?
All of these mobos have lower HT speed, slightly older chipsets etc.
For the upgrade community, this could be a very interesting test!
What if an X4 cpu is seriously slowed down on an AM2 mobo due to HT bandwith limitations?
It would be good to tell those millions that an X2 is the best upgrade option, and that an X4 is a waste of money.
Also, many board manufacturers have stopped updating their website concerning AM2-support, but like my example shows: MSI does not state that my mobo cvan run any modern cpu, except 1 Phenom X3. Nevertheless, www.cpu-upgrade.com states that my mobo supports even most Athlon IIs or Phenom IIs.
So, the lack of cpu-support on these AM2 mobos may have more to do with websites no longer being updated, rather than actual technical compatibility, and hence cpu-support.

Have a nice Sunday!
Carl
a b à CPUs
October 31, 2009 8:40:28 PM

I think the biggest difference you will see running am3 cpu on an am2 motherboard would be in synthetic benchmarks. On another note, buying a cpu that is not officially supported by the board manufacturer and expecting no problems is foolish at best.
October 31, 2009 9:30:13 PM

BadTrip said:
I think the biggest difference you will see running am3 cpu on an am2 motherboard would be in synthetic benchmarks. On another note, buying a cpu that is not officially supported by the board manufacturer and expecting no problems is foolish at best.


In theory, you are 100% correct.
But:
- In the past, I have upgraded several computers with CPUs which "officially" were not stated on the website of the mobo manufacturer. Many of those had even a BIOS which recognised the "oficially not supported" new CPU.
- One should not forget that many companies will only update their website for a certain product as long as they are making money out of it. For some period after that, they will even continue support and update their website. But soon afterwards, they will stop updating their website becuase of cost.
But that does not mean that CPUs which are not listed on their website will not be supported:
BIOS manufacturers usually get lists of new CPUs from CPU manufacturers a long time before they are released on the market.

But you are correct: Installing a CPU which is not officially stated on the mobo manufacturer's website is not without risk, and needs certain research before you know you can go ahead.
a b à CPUs
November 1, 2009 12:10:34 AM

interesting
a b à CPUs
November 1, 2009 5:45:42 AM

Now come on guys & gals
I told you I Installed the AM3 X4 620 on my M2NSLI32 Delux .....lol
All synthetic bench markers refused to show the other two cores..... forget calculating with them.....
I'll try and send the CPUz for both the processors on the same board here....

Heres with the 4400+
http://valid.canardpc.com/show_oc.php?id=657250

Heres with the X4 620
http://valid.canardpc.com/show_oc.php?id=791053

And that is on the Mobo with the latest Bios offered by Asus which enables the a few more processors on that specific board...
a b à CPUs
November 1, 2009 6:13:40 AM

It so seems that the FSB for the M2N32SLI Deluxe is 1000MHz, also the HT for the AMD Athlon 64 X2 4400+ is 1000MHz but the HT for the AMD Athlon II X4 620 is 2000MHz thus it very simply concludes that the processor will calculate and send it's data at a higher speed than the Mobo can handle inturn causing a bottleneck there, secondly the returning of the data is going to be delayed back to the processor which is going to add to the delay, this can slowly result in a build up of a massive bottleneck and slowing down the system drastically.
I guess for the simple man there is a simple conclusion
Choose a processor which has the same HT as the FSB of the Mobo......
That is the simplest solution to a very very deep technical hitch which all the OC'ers fool around with.
a b à CPUs
November 1, 2009 6:18:49 AM

XCom-UFO said:
Jennyh, Thank you for the advice and the HT bandwith list.
I read somewhere on Wiki that AMD CPUs only use half of the 32-bit bandwith of HT, so it's the 16-bit figures we need to look at.

For everybody:
So, I stay stuck on the question wether or not the maximum HT frequency of my mobo (HT 2.0 1Ghz) could bottleneck a modern X2 or X4 Athlon II or Phenom II.
Certainly not while doing office work, but what about playing a "recent" game (I have Bioshock) or video editing.
Does anyone know what HT bandwith an X2 or X4 needs for these types of jobs?
I can only guess that an X4 needs A LOT of bandwith if you want it to run antivirus, Windows, and some other demanding application(s) at once without being bottlenecked by the HT bus.

Or has anyone else ever put an Athlon II or Phenom II on a 690G mobo?
Surely I am not the only one in the world with a 690G mobo, they sold millions of them, so I'm probably not the only one trying to upgrade ;-)
And my mobo is not THAT old, is it? It' not that I'm trying to put a P4 on a Pentium 1 mobo ;-)

Thanks again for all the posts, you guys are very helpful.
Carl


Surprisingly, you will not find bottlenecks in the demanding applications but you'll find them hindering you in the smallest and least processor consuming applications. Thats just something I noticed while I was using my AM3 in my AM2 board....
Since your board has an HT of 2GHz you will not have a problem with the Athlon II X4 if it is a socket AM2+ board.... anything lower will invariably cause a problem. Your next problem is going to be the RAM timings especially since the X4's don't have and L3 cache and have a hard coded mem controller..... you'd better not try to experiment if you're on a tight budget.....
I happen to see you have asked the same question in four different places under four different topics.....
and the answer is still the same in all the topics.... your main issue is the AM2 socket and not the HT or the FSB issue.....
You can jump the generation like I did, AM2 to AM3 , only if the board supports it...... although it is NOT Advisable at all.....
if you want to upgrade you processor than go for the highest AM2 socket processor available and you'll get a life extension of 2 years....... going in for a higher socket is going to bring a whole lot of new issues which we all have discussed here for you.....
a b à CPUs
November 1, 2009 7:18:42 AM

"So, I stay stuck on the question whether or not the maximum HT frequency of my mobo (HT 2.0 1Ghz) could bottleneck a modern X2 or X4 Athlon II or Phenom II. "

As far as I know all the New Athlon II's are AM3 sockets and all the New Phenom II's are eithe AM2+ sockets or AM3 sockets...... None are compatible with your board
AM2+ sockets may be reverse compatible with the AM2 board with a hit on the full potential of the processor..... but your 2GHz HT is going to help and you will not see the or feel the slight difference with the AM2+ socket Phenom II's


Or has anyone else ever put an Athlon II or Phenom II on a 690G mobo?

I did and have pasted the results for you to see....
The links for the two CPUz Reports are below
http://valid.canardpc.com/show_oc.php?id=657250
This is with the earlier Proc
http://valid.canardpc.com/show_oc.php?id=791053
And this is with the new one

Although it's not the same board it's got the 570NB but it's not that different when it comes to the conclusions...... for the processor compatibility...
As you can see from the result that CPUz gave, it show only 2 cores and 2 threads for both the processors when in actual's the second proc is 4 cores..... Logically seeing the whole thing, you will have two dead cores in the heart.... doesn't make a sense to buy a proc with that sort of a board at all....

And my mobo is not THAT old, is it?
It ain't that old......... but it does have it's limitations..... it's a socket AM2 and will not take the AM3 in it's full functionality.....
November 1, 2009 7:26:53 PM

alyoshka said:
It so seems that the FSB for the M2N32SLI Deluxe is 1000MHz, also the HT for the AMD Athlon 64 X2 4400+ is 1000MHz but the HT for the AMD Athlon II X4 620 is 2000MHz thus it very simply concludes that the processor will calculate and send it's data at a higher speed than the Mobo can handle inturn causing a bottleneck there, secondly the returning of the data is going to be delayed back to the processor which is going to add to the delay, this can slowly result in a build up of a massive bottleneck and slowing down the system drastically.


Alyoshka, thank you for the lot of information you gave me.
Strange that your mobo only sees 2 of the 4 cores...
So using a quad core probably is not an optioin for me either.

The articles here at Tomshardware can be confusing:
At several times they say these CPU's are backwards compatbile with most AM2 boards (without the plus),
but during their tests they always user AM2+ or AM3 boards, never an AM2 board.

I think that you are incorrect concerning the quote above though:
All AM3 CPUs use Hypertransport, but they can downclock it to a minimum of 800Mhz (= HT v1.0).
And they will follow the clock on the mobo.
Ie. if your mobo has an 800Mhz HT clock, the CPU will also downclock its HT link to that speed.
So the HT link will work, only, and this is the question I've had since the beginning of this post,
maybe a HT link of 800Mhz or 1Ghz could be a bottleneck for an Athlon II or a Phenom II?
And if it's a bottleneck for an X4, will it still be a bottleneck for an X2, X3?

(Whenever I talk about bottlencks, I mean the ones which have a noticeable impact on speed. If a bottleneck only takes away a few percentages of the performance, then I don't care.)

But thanks for the info about your mobo only recognising half of the cores of the Athlon II x4. It is interesting to know.

Carl

a b à CPUs
November 1, 2009 7:57:12 PM

We can beat this to death but it will be less than 10% on anything but synthetics.
November 1, 2009 8:08:51 PM

BadTrip said:
We can beat this to death but it will be less than 10% on anything but synthetics.



Do you mean that synthetics require the most bandwith?
I thought that video editing, CAD etcetera needed more.
And large databases off course.
I am an Oracle DBA, but on my pc I only have small databases (in virtual environments) for testing purposes, so for them it doesn't matter: Even My Athlon 3800+ deals with them nicely.
a b à CPUs
November 1, 2009 8:12:25 PM

Carl, the HT link has been repeatedly proven to have a little impact on AMD CPUs' performance, but its nice to use a current-generation CPU with technology which was designed for its optimum performance (HT 3 in this case).
If your mobo does not list support for these CPUs, I think they will most probably work but might not get properly recognized (Cores, L3 cache, Speed or Voltages might be set wrong) by the BIOS. In my case, I've got a M3A mobo from ASUS and it does not oficially support Phenom II, yet some guys at ASUS forums have installed them without problems. Bear in mind that the M3A is AM2+, so an AM2 motherboard may not work properly with Quads (especially since Phenom I is not supported).
My advice here would be that you get a cheap AM2+ motherboard with support for Phenom/Athlon II and pick up a CPU according to your budget, in order to be safe with your investment and get all the performance you should out of your quad/triple core CPU.
November 1, 2009 8:14:22 PM

For the folks who want to know what Tomshardware says about these chips, I've been looking at their articles, and I found this article stating the next information:
http://www.tomshardware.com/reviews/phenom-ii-940,2114-...

Compatible And Cost-Efficient: Sockets AM2 And AM2+


When presenting its first Phenom processors next to the Spider platform in November 2007, AMD took great pains to stress their backward compatibility as a selling point. From today’s vantage point, AMD has been true to its promises. The Phenom II will also work in AM2 and AM2+ motherboards, at least as far as the underlying BIOS will allow. For those who want to equip their PCs with a Phenom II, this would ideally require no added costs for a new motherboard or RAM. Various motherboard vendors—most notably, Asus, MSI, and Gigabyte—have already published compatibility lists, and use them to provide information about which of their motherboards will work with the Phenom II, and which BIOS versions are needed for each.

The Phenom II was developed for the AM2+ socket. Nevertheless, it remains backward-compatible with AM2 (as do other new AMD CPUs) and works well with DDR2 RAM. In a few months, AMD will be presenting an AM3 version of its Phenom II processor. This variant will work with faster DDR3 RAM, but to maintain backward compatibility with AM2 and AM2+ sockets, even this model will include a DDR2 RAM interface.

Support
Phenom - Phenom II - Phenom II
Version:
AM2+ - AM2+ - AM3
Socket supported:
AM2,AM2+ - AM2 AM2+ - AM2, AM2+, AM3

So even the AM3s shoul run on AM2 boards.
But that does not answer any of my questions though :-(
November 1, 2009 8:20:15 PM

sanchz said:
If your mobo does not list support for these CPUs, I think they will most probably work but might not get properly recognized (Cores, L3 cache, Speed or Voltages might be set wrong) by the BIOS. In my case, I've got a M3A mobo from ASUS and it does not oficially support Phenom II, yet some guys at ASUS forums have installed them without problems. Bear in mind that the M3A is AM2+, so an AM2 motherboard may not work properly with Quads (especially since Phenom I is not supported).


Sanchz, thank you.
But MSI's website states that my mobo as "AM2+ ready",
and furthermore it IS compatible with the Phenom 1:
In their CPU compatibility list, they state ALL PHENOM 1s which have a tdp of 95W or less (ie the max. tdp for my mobo).

I've sent an email to MSi asking if they plan to add CPUs to their list,
but in the past I've sent them severla emails, and I never got any reply. Not very polite, although I understand they probably get a lot of emails.

But so, my mobo is an AM2 mobo, but it is stated as "AM2+ ready".
a b à CPUs
November 1, 2009 8:21:56 PM

XCom-UFO said:
Do you mean that synthetics require the most bandwith?
I thought that video editing, CAD etcetera needed more.
And large databases off course.
I am an Oracle DBA, but on my pc I only have small databases (in virtual environments) for testing purposes, so for them it doesn't matter: Even My Athlon 3800+ deals with them nicely.



Well you should have no problems then.
November 1, 2009 8:37:13 PM

BadTrip said:
I just looked at your board on MSI's website. It has support for PII triple cores.

http://www.msi.com/index.php?func=prodcpu2&prod_no=1241...

http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Yes, I had noticed that they state 1 Phenom II x3:
It's the "z715", part number HDZ715WCJ3DGI.

Unfortunately - I might be wrong, but - that one does not seem to exist!
I've been googling, and the only info I can find about it is other people asking whether that cpu really exists or not.
And these are people with many different mobos from different manufacturers: Asus, MSI, Gigabyte....
Have they "invented" a cpu to forge compatibility? Or has AMD really announced this chip some day, only to decide later that they would never make it?

To add to the mistery about this z715: Even AMD's website does not state it anywhere... (I mean www.amdcompare.com).
Mistery, as in Halloween :-)

Thanks for the info though.


a b à CPUs
November 1, 2009 8:58:26 PM

the specs of the one on the website and the one on newegg match. Prob a typo, lol
November 1, 2009 9:08:21 PM

BadTrip said:
the specs of the one on the website and the one on newegg match. Prob a typo, lol


I hope you're right.
But the fact that the same "typo" appears on different websites from different mobo manufacturers makes it unlikely to be a typo.
I still think that the z715 is probably a chip that AMD in the end decided not to sell or something.

But you're right, they're both almost exactly the same.
So if I decide to go for a Phenom II, the one you indicate on Newegg is the one I'll probably buy on my own responsibility.
a b à CPUs
November 1, 2009 9:12:43 PM

I was joking about the typo, but being the specs are the same so I doubt there is any difference.
November 1, 2009 10:03:12 PM

BadTrip said:
I was joking about the typo, but being the specs are the same so I doubt there is any difference.


I Hope you're right. The Phenom X3 720 looks promising as an upgrade, even though MSI only states a cpu which seems to be identical, except for its name, the mysterious and non-existent Phenom II x3 "z715".
As it appears as a "real and existing" upgrade cpu for AM2 mobos on websites from several mobo makers,
I'm gonna try to find out why no one can buy this cpu.

If I don't get an answer in this post, then I'll probably make a new post tomorrow,
specifically about this mysterious Halloween-style, non-existing "z715" Phenom II x3.
I wanna know why all mobo manufacturers state it as the only Phenom II which will run on their AM2 mobos (AM2 without the +), while AMD itself doesn't seem to have heard about this CPU itself...

Was this Phenom II x3 "z715" on AMD's roadmap some day or not?
Mystery...

!